The present invention relates to the packaging of food products and more particularly to a polygonal shaped tray-like receptacle that is formed from a single blank of paperboard or the like.
Many different types and designs of containers have been developed for packaging food products and the like in order to meet the needs of particular markets. Recently there has been an increased emphasis on the use of paperboard for such packages, and, more particularly, ovenable paperboard.
Ovenable paperboard is paperboard that is treated to withstand the temperatures encountered in a conventional oven, and, of course, for use in microwave ovens. Paperboard is a particularly good material to use for food packages in microwave ovens because the paperboard does not affect the transmission of the microwaves to the packaged food. In addition, paperboard packages can be easily and readily formed and glued on conventional forming equipment already available. Accordingly, for the purposes of the present invention, the tray disclosed is of the type that is formed from a blank of paperboard that is folded and glued into its final configuration.
U.S. Pat. No. 2,242,684 discloses a baking utensil of the type disclosed herein which is formed from any suitable flexible material such as paper, laminated paper or laminated paper and metal foil. The tray shown in the patent is formed from a single blank of material that is die cut, scored and then placed in a mold where pressure is applied causing the scored serrations in the side walls to be folded flat into pleats. The pleats are then locked into closed position with staples or the like applied to the rim of the tray. In general, the baking tray disclosed in U.S. Pat. No. 2,242,684 performs quite well except that, even with the modifications provided therefor in the flange area, the final configuration ends up with three thicknesses of material in the pleated area and either two or three thicknesses of the tray material in the flange where the pleats are formed. Thus, in some cases, a separate element is needed to fasten the flange and keep the tray in its assembled condition. Meanwhile, U.S. Pat. No. 3,767,108 discloses a similar tray construction for a single serving package wherein the web or gusset panels between the nominal side wall portions are folded and glued to an adjacent side wall portion to produce a leak proof container. The tray so formed is satisfactory, but it also ends up with three thicknesses of the tray material in the gusset area. Moreover, because of the manner in which the blank is scored, the tray has a cup-like or dish-like configuration. In addition, despite the fact that the flange panels overlap one another in the region of the gusset panels, there is no positive locking action between the overlapping panels. Accordingly, in order to overcome the problems of construction with the prior art and to achieve a more reliable and positive action during the tray forming operation, the present invention was developed.